Add -Werror to build_warnings

[Alan Modra]

On Thu, Feb 17, 2005 at 09:18:27PM -0500, Paul Schlie wrote:
> - and/or recommend that GCC-4.0 eliminate that frivolous warning by default.

I'm not going to do any such thing.  I rather like the fact that gcc-4.0
has more warnings, despite it causing some work to make our code warning
free.  Case in point: Better analysis of uninitialized variables found
two places in binutils where we really could use an uninitialized
variable in corner cases.  It also warned about 4 or 5 other places that
were not real problems.  That's a very good ratio.  I'll take 100 false
positives if a compiler finds me one real error..

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre